(Reuters) - Federal prosecutors said on Tuesday they would not file any charges in the Florida cyberstalking investigation of Paula Broadwell, the biographer whose affair with former CIA chief David Petraeus led to his resignation.

Anonymous emails that Broadwell sent to Jill Kelley, a Tampa socialite who knew Petraeus, prompted an FBI investigation that exposed Broadwell's affair with the retired U.S. Army general known for his success in the Iraq war. Petraeus resigned from the CIA last month.

"After applying relevant case law to the particular facts of this case, the United States Attorney's Office for the Middle District of Florida has decided not to pursue a federal case regarding the alleged acts of 'cyberstalking' involving Paula Broadwell," the U.S. Attorney's office in Tampa, Florida, said in a statement.

The emails were never made public. They reportedly indicated that Broadwell viewed Kelley as a rival and asked her to leave Petraeus alone.

The sex scandal involving the married retired four-star general and his biographer, an Army reserve intelligence officer who is also married, provided fodder for comedians and raised questions about online privacy.

Broadwell's attorney, Robert Muse, said: "We are very pleased with the decision, and are pleased with the professionalism of the Tampa United Sates Attorney's Office."

Broadwell was also under investigation for her handling of classified materials and it was unclear on Tuesday whether that investigation was still continuing.

"Our office cannot comment outside of our statement on the cyberstalking investigation," a spokeswoman for the Tampa prosecutor said.

A Justice Department spokesman in Washington also declined to comment on whether that investigation was continuing or whether Broadwell could still be charged with crimes other than cyberstalking.

Broadwell's spokeswoman, Dee Dee Myers, said Broadwell was unaware of any further investigation targeting her and that the cyberstalking inquiry "was the only investigation that Paula had been notified she was a subject of."

FBI agents found a substantial amount of classified information on Broadwell's personal computer when they searched her North Carolina home with her consent in November. Both she and Petraeus have told investigators they did not share security secrets.

Sources briefed on the investigation previously told Reuters the documents date from before August 2011, when Petraeus took up his post at the CIA and the two started their affair. None of the material comes from the CIA, the sources said.

Broadwell had a security clearance that allowed her to handle sensitive documents but would still have to comply with strict rules that lay out how sensitive materials must be protected.

Broadwell's security clearance has been suspended. It could be revoked and she could face harsher penalties if it is found that she mishandled classified data.